RESET-LD-SPECIALS

Roughly speaking, the ld specials are certain state global
variables, such as current-package, ld-prompt, and
ld-pre-eval-filter, which are managed by ld as though they were
local variables. These variables determine the channels on which ld
reads and prints and control many options of ld. See ld for
the details on what the ld specials are.

This function, reset-ld-specials, takes one Boolean argument, flg.
The function resets all of the ld specials to their initial,
top-level values, except for the three channel variables,
standard-oi, standard-co, and proofs-co, which are reset to their
initial values only if flg is non-nil. Of course, if you are in a
recursive call of ld, then when you exit that call, the ld specials
will be restored to the values they had at the time ld was called
recursively. To see what the initial values are, inspect the value
of the constant *initial-ld-special-bindings*.